This guide describes database features that support applications using Large Object (LOB) datatypes. The information in this guide applies to all platforms and does not include system-specific information.

This preface contains these topics:


Oracle Database Application Developer's Guide - Large Objects is intended for programmers developing new applications that use LOBs, as well as those who have already implemented this technology and now want to take advantage of new features.

The increasing importance of multimedia data as well as unstructured data has led to this topic being presented as an independent volume within the Oracle Application Developers documentation set.

Feature Coverage and Availability

Oracle Database Application Developer's Guide - Large Objects contains information that describes the features and functionality of Oracle Database 10g.

What You Need To Use LOBs

The database includes all of the resources you need to use LOBs in your application; however, there are some restrictions on how you can use LOBs as described in the following:

Documentation Accessibility

Our goal is to make Oracle products, services, and supporting documentation accessible, with good usability, to the disabled community. To that end, our documentation includes features that make information available to users of assistive technology. This documentation is available in HTML format, and contains markup to facilitate access by the disabled community. Accessibility standards will continue to evolve over time, and Oracle is actively engaged with other market-leading technology vendors to address technical obstacles so that our documentation can be accessible to all of our customers. For more information, visit the Oracle Accessibility Program Web site at

Accessibility of Code Examples in Documentation

Screen readers may not always correctly read the code examples in this document. The conventions for writing code require that closing braces should appear on an otherwise empty line; however, some screen readers may not always read a line of text that consists solely of a bracket or brace.

Accessibility of Links to External Web Sites in Documentation

This documentation may contain links to Web sites of other companies or organizations that Oracle does not own or control. Oracle neither evaluates nor makes any representations regarding the accessibility of these Web sites.

TTY Access to Oracle Support Services

Oracle provides dedicated Text Telephone (TTY) access to Oracle Support Services within the United States of America 24 hours a day, seven days a week. For TTY support, call 800.446.2398.

Related Documents

For more information, see the following manuals:

Oracle Database error message documentation is only available in HTML. If you only have access to the Oracle Documentation CD, you can browse the error messages by range. Once you find the specific range, use your browser "find in page" feature to locate the specific message. When connected to the Internet, you can search for a specific error message using the error message search feature of the Oracle online documentation.

Many of the examples in this book use the sample schemas, which are installed by default when you select the Basic Installation option with an Oracle Database installation. Refer to Oracle Database Sample Schemas for information on how these schemas were created and how you can use them yourself.


You can access the Oracle development environment for multimedia technology in a number of different ways.

Basic References

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This section describes the conventions used in the text and syntax examples of this documentation set. It describes:

Conventions in Text

We use various conventions in text to help you more quickly identify special terms. The following table describes those conventions and provides examples of their use.

Convention Meaning Example
Bold Bold typeface indicates terms that are defined in the text or terms that appear in a glossary, or both. When you specify this clause, you create an index-organized table.
Italics Italic typeface indicates book titles or emphasis. Oracle Database Concepts

Ensure that the recovery catalog and target database do not reside on the same disk.

UPPERCASE monospace (fixed-width font) Uppercase monospace typeface indicates elements supplied by the system. Such elements include parameters, privileges, datatypes, RMAN keywords, SQL keywords, SQL*Plus or utility commands, packages and methods, as well as system-supplied column names, database objects and structures, usernames, and roles. You can specify this clause only for a NUMBER column.

You can back up the database by using the BACKUP command.

Query the TABLE_NAME column in the USER_TABLES data dictionary view.


lowercase monospace (fixed-width font) Lowercase monospace typeface indicates executables, filenames, directory names, and sample user-supplied elements. Such elements include computer and database names, net service names, and connect identifiers, as well as user-supplied database objects and structures, column names, packages and classes, usernames and roles, program units, and parameter values.

Note: Some programmatic elements use a mixture of UPPERCASE and lowercase. Enter these elements as shown.

Enter sqlplus to open SQL*Plus.

The password is specified in the orapwd file.

Back up the datafiles and control files in the /disk1/oracle/dbs directory.

The department_id, department_name, and location_id columns are in the hr.departments table.

Set the QUERY_REWRITE_ENABLED initialization parameter to true.

Connect as oe user.

The JRepUtil class implements these methods.

lowercase monospace (fixed-width font) italic Lowercase monospace italic font represents placeholders or variables. You can specify the parallel_clause.

Run Uold_release.SQL where old_release refers to the release you installed prior to upgrading.

Conventions in Syntax Examples

Syntax examples illustrate SQL, PL/SQL, SQL*Plus, or other command-line statements. They are displayed in a monospace (fixed-width) font and separated from normal text as shown in this example:

SELECT username FROM dba_users WHERE username = 'MIGRATE'

The following table describes typographic conventions used in syntax examples and provides examples of their use.

Convention Meaning Example
[ ] Brackets enclose one or more optional items. Do not enter the brackets. DECIMAL (digits [ , precision ])
{ } Braces enclose two or more items, one of which is required. Do not enter the braces. {ENABLE | DISABLE}
| A vertical bar represents a choice of two or more options within brackets or braces. Enter one of the options. Do not enter the vertical bar. {ENABLE | DISABLE}


... Horizontal ellipsis points indicate either:
  • That we have omitted parts of the code that are not directly related to the example

  • That you can repeat a portion of the code

CREATE TABLE ... AS subquery;

SELECT col1, col2, ... , coln FROM employees;

Vertical ellipsis points indicate that we have omitted several lines of code not directly related to the example.
9 rows selected.
Other notation You must enter symbols other than brackets, braces, vertical bars, and ellipsis points as shown. acctbal NUMBER(11,2);

acct CONSTANT NUMBER(4) := 3;

Italics Italicized text indicates placeholders or variables for which you must supply particular values. CONNECT SYSTEM/system_password

DB_NAME = database_name

UPPERCASE Uppercase typeface indicates elements supplied by the system. We show these terms in uppercase in order to distinguish them from terms you define. Unless terms appear in brackets, enter them in the order and with the spelling shown. However, because these terms are not case sensitive, you can enter them in lowercase. SELECT last_name, employee_id FROM employees;


DROP TABLE hr.employees;

lowercase Lowercase typeface indicates programmatic elements that you supply. For example, lowercase indicates names of tables, columns, or files.

Note: Some programmatic elements use a mixture of UPPERCASE and lowercase. Enter these elements as shown.

SELECT last_name, employee_id FROM employees;

sqlplus hr/hr